1. Field of the Invention
The present invention relates to a method of producing a semiconductor package, an apparatus for producing a semiconductor package, and an adhesive film, more particularly relates to a method of producing a semiconductor package called “system-in-package (SiP)” and an apparatus for producing a semiconductor package and an adhesive film used for the same.
2. Description of the Related Art
Demand for reducing the size, thickness, and weight of digital video cameras, digital mobile phones, notebook computers, and other portable electronic devices has been growing increasingly stronger. To meet with this, VSLIs and other semiconductor packages have been reduced 70% in size in the past three years. On the other hand, how to raise the mounting density of components on mounting boards (printed circuit boards) has been the subject of much R&D for electronic circuit devices comprising such semiconductor packages mounted on printed circuit boards.
For example, semiconductor packages have been shifting from the DIP (dual in-line package) and other surface mounted types to flip-chip mounted types providing the pad electrodes of semiconductor chips with bumps made of solder, gold, etc. and connecting the chips to the circuit boards through the bumps in a state where the surfaces provided with bumps face the boards (face down).
Further, types forming multilayer interconnects also known as reinterconnect layers on the semiconductor chips and the complicated types known as “system-in-packages (SiP)” packaged by burying coils or other passive devices or other semiconductor chips between insulating layers insulating the reinterconnect layers formed on the semiconductor chips are being developed.
As the method of producing a semiconductor package burying other semiconductor chip between the insulating layers insulating the reinterconnect layers formed on semiconductor chip, the method of die bonding other semiconductor chip (hereinafter sometimes simply referred to as “semiconductor chip”) on semiconductor chip serving as a substrate (hereinafter sometimes simply referred to as “substrate”) and forming insulating layers comprised of resin layers containing the reinterconnect layers covering the same is widely known.
In this method of producing a semiconductor package, as the method of die bonding the semiconductor chip on the substrate, the method of grinding down the wafer from the back side when the semiconductor chip is supplied in the wafer state before dicing, laminating a die-attach film (adhesive film) in the wafer state, dicing the wafer to obtain the individual semiconductor chips, and mounting the obtained semiconductor chip to the substrate face up or face down is widely used.
On the other hand, when the semiconductor chips are supplied in a state already separated into individual units, usually they are supplied on 4 inch diameter chip trays and are mounted face up or face down on the substrates of the SiPs by die bonding. Here, there are restrictions derived from the multiple layers in the wafer state and the resin forming the SiPs etc., so the semiconductor chips of the SiP have to be reduced in thickness to about 50 μm. The individually separated semiconductor chips are reduced in thickness by the following procedure. That is, a package use monitor wafer is attached to the center of a protective tape for use in grinding down the semiconductor chips, the individually separated semiconductor chips are arranged around it, and the chips are ground down while monitoring the thickness of the monitor wafer.
The ground down thin semiconductor chip is then reattached to transfer sheet etc. for mounting on the substrate and supplied to a die bonder. Here, for example when using an insulating paste in a die bonder for bonding face up, a scrubbing operation becomes necessary to make the paste a uniform thickness. However, thin semiconductor chip lacks strength and is liable to break, so cannot be scrubbed. Therefore, thin semiconductor chip cannot be bonded by paste. Accordingly, thin semiconductor chip is bonded using a uniform thickness die-attach film.
A die-attach film, as shown in the schematic view of FIG. 1, is usually supplied in the form of a roll R1. This has a width W1 far greater than the width of the semiconductor chip, so at the time of actual use, as shown in the schematic view of FIG. 2, it is cut corresponding to the width W2 of the semiconductor chip to obtain the roll R2. As shown in the schematic view of FIG. 3, the film is fed out and cut from the roll R2 by a cutter 100 into the size of the semiconductor chip. The semiconductor chip 102 is then bonded to the thus obtained predetermined sized piece of die-attach film 101 using a collet 103. The thus obtained semiconductor chip with the piece of die-attach film bonded to it is transported by a suction collet to the substrate and mounted on the substrate.
In the above method however, it is necessary to prepare a roll cut to the width of the chip. When handling several types of semiconductor chips of different sizes, the loss ends up becoming greater. Further, precise bonding to the semiconductor chip after cutting is difficult. The piece of die-attach film easily sticks out from the semiconductor chip. When actually sticking out, the part where the piece of die-attach film stick out lacks photosensitivity and via holes cannot be formed, so interconnect defects are liable to occur.
Summarizing the problems to be solved by the invention, when mounting an individually separated thin semiconductor chip on a substrate, the loss of the die-attach film (adhesive film) is great and the piece of die-attach film sticks out from the semiconductor chip to easily cause an interconnect defect.